Anaphylactic Shock

Abstract

Anaphylaxis is a life threatening hypersensitivity reaction that can cause shock. Epidemiology studies show anaphylaxis and anaphylactic shock is relatively rare, but its incidence is increasing. A review of the pathophysiology of anaphylaxis can provide insight into clinical decisions. Diagnosing anaphylaxis can be difficult as symptoms and history are not always obvious. Diagnostic guidelines provide an objective tool to assess for anaphylaxis. Early intervention during anaphylaxis may prevent development of shock. Management is focused on circulation support with epinephrine and IV fluids, and airway maintenance. Following an acute anaphylactic reaction, patients should be provided with a referral for follow up and educated on avoidance of triggers and use of epinephrine autoinjectors.

Allergic Anaphylactic Risk in Farming Activities: A Systematic Review

“…Clinical manifestation appears polymorphic and insidious with a range of severity, classified in different scales: the most usual are proposed by Mueller, Ring and Brown [ 48 , 49 , 50 ]. In about 20% of cases, new symptoms develop, after the acute phase, usually within a mean time of 8–10 h (interval of 0.2–72 h) [ 4 ], without a new trigger exposure (biphasic anaphylaxis). More infrequently, persistent anaphylaxis occurs when symptoms persist for 5–32 h [ 51 ].…”

“…The pathophysiology commonly underlies an IgE-mediated immune responses as Gell-Coombs Classification type 1 hypersensitivity (immediate hypersensitivity): the antigen-IgE interaction on basophils and mast cells previously sensitized, causes degranulation and release of preformed chemical mediators (e.g., histamine, tryptase, heparin) and de novo syntheses (e.g., leukotrienes, PAF, PGD2), which leads a diffuse contraction of the smooth muscle, resulting in bronchoconstriction, vomiting or diarrhea, for example; as well as an increase in capillary permeability and dilation of blood vessels (e.g., angioedema, urticaria) and a decrease of vascular tone (e.g., hypotension, syncope) [ 2 , 4 ]. At times, biochemical pathways of anaphylaxis are set off by immune cells other than IgE (e.g., IgG, complexes of complement)—traditionally defined “anaphylactoid reaction”—or even through the absence of an immune-mediated cellular activation (e.g., hyperosmolar substances, contrast, anesthetic drugs, physical exercise) [ 2 , 3 , 4 ].…”

“…The global burden of this phenomenon is still uncertain [ 4 ], because this syndrome is often “under-recognized” or “under-diagnosed” [ 1 ]. During the last few years, various international studies have shown an upward trend in the rate of anaphylaxis, even if the incidence and prevalence differ between the European and American populations, especially regarding the occurrence of fatal outcomes.…”

“…During the last few years, various international studies have shown an upward trend in the rate of anaphylaxis, even if the incidence and prevalence differ between the European and American populations, especially regarding the occurrence of fatal outcomes. In Europe, the calculated prevalence is currently around 3%, while in the United States it ranges between 0.05–2% [ 4 ]. The increase in the frequency recorded globally appears to be conditioned not only by changes in the diagnostic definition and management of the event, but also by many different variables, such as triggers, socio-demographic dates, geographical area, seasonal variations, older age, gender, atopy and comorbidities (e.g., allergic asthma, cardiovascular disease) [ 4 ].…”

“…In Europe, the calculated prevalence is currently around 3%, while in the United States it ranges between 0.05–2% [ 4 ]. The increase in the frequency recorded globally appears to be conditioned not only by changes in the diagnostic definition and management of the event, but also by many different variables, such as triggers, socio-demographic dates, geographical area, seasonal variations, older age, gender, atopy and comorbidities (e.g., allergic asthma, cardiovascular disease) [ 4 ]. In the work environment, some of the main provocative agents, (together with others, which are less common) can cause an allergic response, exposing workers to a significant risk factor, which is likely to arouse a severe or fatal anaphylactic reaction.…”